Producing molybdenum alloys



1 .poration of Delaware No Drawing t The present invention relates tonew and usei ful improvements in alloying molybdenum with ferrous metalsand moreparticularly' toja novel 'nd improved molybdenum addition agenti I Heretofore, molybdenum-bearing ferrous alloys havebeen, produced bythe addition of molybdenum to the iron or steel either as calciummolybdate, some other molybdic acid salt, or as ferro molybdenunnHowever, each of these materials has its limitations and cannot beuseduniversally "for onefreason or another. Calcium \molybdate and otherequivalent molybdic acid salts are of satisfactory for the production ofa .widerange of ferrous alloysin the blast furnace as well as in l5theladle; but arenot satisfactoryfor the production of a11oys,- as inthe electric furnace, where slag is objectionable. Ferromolybdenum isconiderably more costly than {calcium molybdate and its use isgenerally-restricted to those alloys for which calcium molybdate is]notsuited, al-

though,,except for the costof the material it is of quite generalapplication. Calcium molybdate, however, requires the, production of thecompound from roasted molybdenite, eitherby mixnga'nd heating to hightemperatures, or by mixmg, wetting jandbriquetting. 1

Theprior patents and literature describe other processesiofproducingmolybdenum alloys which have not come into commercial use, orare of very 30 limited commercialv application, and inseveral of them,themolybdenum is described as being I added to" the blast furnace, or tothe molten ferrousmetal, in the form of roasted molybdenite or molybdictrioxide. These processes have 35 proved to be of. no commercial value,due to the g high loss of molybdenum through volatilization andentrainment, as molybdic trioxide is a very light powder and has arelatively low volatilizaq tion point. Consequently, these processeswill Y, 40 produce a commercially satisfactory recovery of -molybdenumonly where the molybdenum trioxide, or roastedmolybdenite, is buried inthe charge. and will be trapped or absorbed. by the upper layers of thecharge before it escapes from 45 the furnace. However, when the furnaceis charged in thismanner, only one alloy can be produced from the chargeand it is generally not desired to produce solarge an amount of any pparticularmolybdenum alloy. Where the molyb-, 5 'denumtrioxide orroasted molybdenite is thrown in on top of "the slag, it is generallyvolatillzed before itmixes with the slag] and only a small portion isrecovered in thealloy.

, Thepresent invention has for its object the 55 provision of a noveland improved composition of Application Jan 3 Claims. (01.15-3) o,

, matter for the "introduction of molybdenum into Arthur New York, n.11., assignor to Climax Molybdenum Company,

New York, N. Y., a corferrous alloys, and also provides a novelandimproved form of molybdenum trioxide.

In accordance with the present invention, the,

' molybdenum is added tothefurnace or ladle in 5 the form of briquettescomposed" of roasted molybdenite concentrates or molybdenum tri-' Hoxide intimately mixed with a relatively small amount of still pitch; soas to forma hard, compact mass of relatively high specific gravity.

These briquettes are suitable for the production of ferrous molybdenumalloys either in the blast,

furnace, electric furnace, or by the addition of the briquettes to themolten metal in the ladle. By the use of these briquettes, molybdenummay be introduced into the ferrous alloy practically withoutlossup to 1%molybdenum in the final alloy, and with only relatively small losses ofmolybdenum even where the alloy contains as much as 15% molybdenum.

Specifically, the briquettes of the present inventionare preferablyformed from roasted molybdeniteconcentrates, which are the technicalgrade of molybdenumtrloxide and contain from '19gto 90% ofmolybdenumtrioxide. This roasted molybdenite is' mixed with ,a-quantity of still-7 pitch whichserves as a binder for the roasted molybdenitafand theproportions are such that the briquettes contain-from 88 to 90% roastedmolybdenite and from 10% to 12% ofstill-pitch. 3o 9 These briquettes arepreferably cylindrical and may conveniently contain a predetermined'anduniform amount of molybdenum. In practice, it is convenient for them tohave a molybdenum content of 2.50 pounds, as this size makes for easyhandling, and these briquettes are of, sufficient size andweight to sinkreadily through the slag or into the molten ferrous metal. The uniformmolybdenum content of these briquettes expedites the addition of thecorrect amount of molyb- 40 denum. 1 1 Q v The use of pitch as a binderfor the roasted molybdenite is particularly desirable as itgenerallycontains more than 90% carbon, and the quantity specified not onlyserves to bind the roasted concentrate firmly together into a hardcompact mass, but also approximately provides the correctstoichiometrical quantity of carbon to combine with the oxygen in theroasted concentrate; thereby preventing a change inthe carbcn content ofthe final ferrous alloy. H The briquettes of the present invention areex tremely economical due to the low cost and small of. the addedmaterial and also to the amount fact that they can be manufacturedsimply and pitch.

1. An alloying briquette comprising a solid mass of about 90% roastedmolybdenite concentrates and about 10% pitch binder.

2. An alloying briquette comprising a solid mass of roasted molybdeniteconcentrates and a relatively small amount of pitch intimately mixedtherewith and serving as a binder.

3. A composition of matter for use in producing ferrous-molybdenumalloys consisting of an intimate mechanical mixture of roastedmolybdenite concentrates and a relative small amount of ARTHUR LINZ.

